Abstract
In this work, we examine the use of the amidoxime functional group grafted onto a hierarchical
porous carbon framework for the selective capture and removal of carbon dioxide from
combustion streams. Measured CO2/N2 ideal selectivity values for the amidoxime-grafted
carbon were significantly higher than the pristine porous carbon with improvements of 65%.
Though the overall CO2 capacity decreased slightly for the activated carbon from 4.97 mmol g-1
to 4.24 mmol g-1 after surface modification due to a reduction in the total surface area, the
isosteric heats of adsorption increased after amidoxime incorporation indicating an increased
interaction of CO2 with the sorbent. Total capacity was reproducible and stable after multiple
adsorption/desorption cycles with no loss of capacity suggesting that modification with the
amidoxime group is a potential method to enhance carbon capture.
